Diaphragm



FIG. 1 is a perspective view of a diaphragm showing my new design;

FIG. 2 is a bottom view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a side view thereof; and,

FIG. 5 is a cross-sectional side view thereof. 

The ornamental design for a diaphragm, as shown and described. 